[libcxx-commits] [libcxx] [libc++] Fixes lit portability issues. (PR #72435)

[Stephan T. Lavavej via libcxx-commits]

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@@ -29,7 +29,13 @@ def appendToSubstitution(substitutions, key, value):
     return [(k, v + " " + value) if k == key else (k, v) for (k, v) in substitutions]
 
 
-std = getSubstitution("%{cxx_std}", config)
+# External users of the LLVM test suite might not have set the substitutions.
+std = ""
+try:
+    std = getSubstitution("%{cxx_std}", config)
+except:
+    pass
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StephanTLavavej wrote:

We have files like https://github.com/microsoft/STL/blob/46843b3bf320c6070ff63e978936bcf898e5a2bc/tests/std/lit.site.cfg.in . It sounds like we might need to add `config.substitutions.append(("%{cxx_std}", "cxx26"))` or maybe `lit_config.BLAH`?

> I'm not sure why you're doing something significantly different here

Me neither - @CaseyCarter might know more though.

https://github.com/llvm/llvm-project/pull/72435